Valve mechanism and method for making same

ABSTRACT

A diaphragm valve including a main valve body and a ring member welded to the main valve body, and a flexible diaphragm having an outer periphery welded to the ring member. The weldment between the main valve body, the ring member, and the diaphragm, provide a hermetic seal for the chamber cavity of the diaphragm valve. The diaphragm may include an inner periphery welded to an axially movable valve member, also for providing a hermetic seal of the chamber cavity. In other embodiments, the outer periphery of the diaphragm is clamped to seal the chamber cavity by a bonnet being welded to the valve body. 
     A seal arrangement includes a groove provided in a surface surrounding a port, and an elastic sealing material disposed in the groove. The sealing material includes a portion extending out of the groove, and the groove and sealing material are configured so as to provide a void between the extending portion and the sidewall portions of the groove such that material may elastically fill the void when it is engaged by a valve member, and such that it may return to its original shape upon disengagement of the valve member without substantial permanent deformation.

TECHNICAL FIELD

The present invention relates to the valve art in general. Moreparticularly, the invention relates to an improved diaphragm valve andto improvements in valve seals and valve diaphragms.

BACKGROUND ART

Diaphragm valves of known types typically include a main valve bodydefining a valve cavity and inlet and outlet passages communicating withthe valve cavity. A flexible metal diaphragm is mounted to the valvebody in order to provide a hermetic seal for the valve cavity. Metaldiaphragm valves are often used in systems handling purified fluids,since the diaphragm is able to provide total hermetic sealing betweenthe valve cavity (process side) and the valve operating mechanism. Metaldiaphragm valves are frequently employed in the semiconductormanufacturing industry.

In some diaphragm valves, the flexible diaphragm is a thin metalcircular disk having its outer periphery attached to the valve body byclamping. A bonnet member is screwed into the valve body so as to holdor clamp the disk outer periphery between the bonnet member and thevalve body. A valve operating stem is arranged for axially pushing acentral portion of the circular diaphragm disk to directly or indirectlyengage the inlet passage of the valve body.

In other diaphragm valves, the flexible diaphragm is a thin metalannular disk through which the valve operating stem extends. The annulardisk diaphragm has its outer periphery attached to the valve body andits inner periphery attached to the valve operating stem. U.S. Pat. No.4,671,490 describes a diaphragm valve of this type in which the valveoperating stem extends through the annular diaphragm disk and includes amain stem and a stem tip connected to the main stem. The annular diskouter periphery is welded to the valve body and clamped to the valvebody by a threaded bonnet screwed into the valve body, while the annulardisk inner periphery is welded to the stem tip of the valve operatingstem and clamped between the stem tip and the main stem.

As is apparent, the manner in which the diaphragm is mounted indiaphragm valves is important since failure of the diaphragm connectionswill result in leaking, which could result in the release of dangerousor damaging fluids. Attempts to improve the diaphragm mounting havesignificantly increased the complexity and cost associated with theoverall valve structure and its manufacture.

Diaphragm valves including bonnets which are screwed into valve bodiesfor clamping diaphragms require expensive high-precision machined parts.During assembly, a precise torque must be applied to the threaded bonnetin order to adequately clamp the diaphragm outer periphery to the valvebody. If the applied torque is too small, the coupling of the diaphragmouter periphery may not sufficiently seal the valve chamber cavity, andif the torque is too large, the diaphragm may be damaged which wouldalso lead to sealing failure. The threaded bonnet can also permitcontamination to enter the valve's working mechanism. Furthermore,conventional diaphragm valves frequently are manufactured with a largenumber of complex parts which lead to increased manufacturing andassembly costs, and which may increase the opportunity for valvefailure.

What is needed is a diaphragm valve having a reliably sealed valvechamber cavity but which is easy and inexpensive to manufacture andmaintain.

DISCLOSURE OF THE INVENTION

According to one aspect of the subject invention, there is provided anew and improved diaphragm valve construction including a bonnetcovering a diaphragm and being non-releasably coupled to the valve bodyby at least one weld such that the diaphragm is non-releasably securedwithin the bonnet. In one embodiment, the bonnet is welded directly tothe valve body such that the bonnet clamps the diaphragm outer peripheryto a clamping surface of the valve body to provide hermetic sealing forthe valve chamber cavity. In another embodiment, the valve body includesa ring member to which the diaphragm outer periphery is welded and thebonnet is in turn welded to the ring member.

According to this aspect of the invention, an all-welded diaphragm valveconstruction is provided to connect the diaphragm outer periphery in thevalve body for providing a hermetic seal for the valve chamber cavity.The all-welded construction eliminates the use of complicated andexpensive threaded bonnet/valve body assemblies, and permits anextremely reliable diaphragm valve to be inexpensively manufactured witha reduced number of parts and/or with simplified procedures.

According to a further aspect of the present invention, them is provideda diaphragm valve which includes a flexible diaphragm having an outerperiphery welded to a ring member. The ring member is welded to a mainvalve body thereby forming the valve chamber cavity defined by the mainvalve body, the ting, and the diaphragm. In this manner, the weldmentcomprising the main valve body, the ring member, and the diaphragm,provide a reliable hermetic seal for the valve chamber cavity, while theuse of threaded bonnet/valve body assemblies for clamping the diaphragmouter periphery is eliminated.

Advantageously, the outer periphery may first be welded to the ringmember, and then the ring member is welded to the valve body. The weldbetween the ring member and the diaphragm outer periphery consequentlyis positioned substantially inside the valve chamber cavity. In onepreferred embodiment, the ring member includes an internally projectingflange, and the outer periphery of the diaphragm is welded to the ringmember such that the ring member flange is arranged over a face of thediaphragm opposed to the valve chamber cavity. The diaphragm may alsoinclude an outer rim at the outer periphery and an outer flangeextending from the outer rim, and the outer flange is welded to the ringmember.

According to another aspect of the invention, there is provided adiaphragm valve which includes a flexible annular diaphragm having anouter periphery welded to a ring member and an inner periphery welded toa valve member extending through the central axis of the annulardiaphragm. The ring member is welded to a main valve body. The weldmentcomprising the main valve body, the ring member, the diaphragm, and thevalve member provide a reliable hermetic seal for the valve chambercavity, while the use of threaded bonnet/valve body clamping assembliesis eliminated.

According to further aspects of the invention, a number of improveddiaphragm structures are provided. One diaphragm structure includes aplurality of concentric ridges and valleys to provide a corrugationwhich allows the diaphragm to be made of thicker material and stillretain flexibility. Other diaphragm structures include an outerperiphery rim and an outer flange extending from the outer rim or anannular-shaped diaphragm having an inner periphery rim and an innerflange extending from the inner rim. The inner and outer flanges may bewelded to cylindrical surfaces respectively of a movable valve memberand a valve ring member. The flange weldments provide improved couplingof the diaphragm in the valve, while the corrugation provides animproved load resistance of the diaphragm in the valve.

Still according to another aspect of the invention, there is provided anew and improved valve assembly having a circumferential groove providedin a surface of the valve body surrounding a port, and an elasticsealing material which is at least partially disposed in thecircumferential groove and which includes an extension portion partiallyextending from the circumferential groove past the valve body surface.The circumferential groove is configured to provide a void between theextension portion and sidewall portions of the groove such that materialof the extension portion can at least partially fill the void when avalve member engages the extension portion and such that the extensionportion can return substantially to its original configuration when thevalve member disengages the extension portion. The sealing material isallowed to elastically deform in the void between the sealing materialextension portion and the groove sidewall portions when the valve memberis closed, and the sealing material returns to its original shape whenthe valve member is open without the occurrence of any significantpermanent plastic deformation which leads to a long life of the sealingarrangement.

These and other advantages of the present invention will become clear tothose skilled in the art upon a study of the following detaileddescription of the invention and of the several figures of the drawings,in which like elements are numbered alike and which show the preferredembodiments of the invention and which are not intended for the purposeof limiting same.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of a diaphragm valve inaccordance with the present invention;

FIG. 2 is an exploded isometric view showing the various parts of thediaphragm valve of FIG. 1;

FIG. 3 is a cross-sectional side elevation taken along line 3--3 of FIG.1, with the valve member in a center position;

FIG. 4 is an enlarged cross-sectional elevation view of a diaphragmassembly of the valve of FIG. 3;

FIG. 5 is an enlarged close-up view at the inner periphery of thediaphragm of the valve of the preceding Figures;

FIG. 6 is an enlarged close-up view at the outer periphery of thediaphragm of the valve of the preceding Figures;

FIG. 6a is an enlarged cross-sectional elevation view similar to FIG. 4showing another embodiment of a diaphragm assembly in accordance withthe present invention;

FIG. 7 is an enlarged cross-sectional view of the valve of FIG. 3 withthe valve poppet in a closed sealing position;

FIG. 8 is an enlarged cross-sectional view of the valve of FIG. 3 withthe valve poppet in an open non-sealing position;

FIG. 9 is an enlarged plan view of a valve seal arrangement taken alongline 9--9 of FIG. 8;

FIG. 10 is an enlarged cross-sectional elevation side view of the valveseal arrangement of FIG. 9, showing the use of a swage tool in amanufacturing step of the valve seal;

FIG. 11 is an enlarged cross-sectional elevational view of the valveseal arrangement of FIG. 9, showing deformation about the valve portafter a swage operation;

FIG. 12 is an enlarged cross-sectional elevational view of the valveseal arrangement of FIG. 9 with the sealing material engaged by thevalve poppet and in an elastically compressed state; and

FIG. 13 is a cross-sectional elevation view of a bonnet to valve bodyweld connection of another embodiment of a diaphragm valve in accordancewith the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION

Referring to FIGS. 1, 2 and 3, a diaphragm valve 10 according to oneaspect of the invention includes a main valve body 12, a ring member 14,and a handle 16. Diaphragm valve 10 further includes a flexible annulardiaphragm 18, an elongated valve member 20, a valve drive mechanism 22,and a bonnet 24.

Ring member 14 is welded to main valve body 12 and together therewithsubstantially forms the valve body for diaphragm valve 10, while handle16 is rotatably associated with the valve body for operating diaphragmvalve 10 in a manner described in more detail hereinafter. Main valvebody 12 is provided with a cylindrical flange 12a, while ring member 14also includes a cylindrical flange 14a which is aligned and welded withflange 12a.

Main valve body 12 is further provided with an inlet passage 12b and anoutlet passage 12c, and a chamber cavity 12d having an open mouth 12e.Inlet passage 12b communicates with chamber cavity 12d at a first port12f, while outlet passage 12c communicates with chamber cavity 12b at asecond port 12g. Diaphragm valve 10 may be connected in a fluid flowline such that fluid would typically flow, when the valve is open, inthrough inlet passage 12b and first port 12f into chamber cavity 12d,and out through second port 12g and outlet passage 12c. Main valve body12 defines a valve axis A. Chamber cavity 12d is delimited by agenerally cylindrical surface 12h extending symmetrically about axis A,and a substantially planar surface 12i which is blended with cylindricalsurface 12h by a rounded portion surface 12j. Inlet port 12f is providedin planar surface 12i. Inlet port 12f is substantially circular and alsoextends symmetrically about axis A.

Elongated valve member 20 includes a poppet 26, an annular washer 28,and a stem 30 which are mutually connected by means of a threaded rodmember 32 which extends through a bore 34 in stem 30 and a centralaperture 36 of washer 28, and which is screwed into a threaded bore 38of poppet 26. Washer 28 is interposed between stem 30 and poppet 26.Elongated valve member 20 extends along axis A through annular diaphragm18. Elongated valve member 20 is adapted for moving along axis A betweenclosed and open positions, as will be described hereinafter.

With additional reference to FIG. 4, annular diaphragm 18 has a centralaxis D, an inner periphery 40 welded to poppet 26, and an outerperiphery 42 welded to ring member 14. Central axis D of annulardiaphragm 18 coincides with axis A of diaphragm valve 10. The weldmentcomprising main valve body 12, ring member 14, annular diaphragm 18, andelongated valve member 20 is such as to provide a hermetic seal forchamber cavity 12d of the valve body.

Valve drive mechanism 22 is coupled to valve member 20 for driving valvemember 20 along axis A between a closed position in which poppet 26 isin a sealing engagement relative to first port 12f and an open positionin which poppet 26 is not in a sealing engagement relative to first port12f.

An annular retainer 44 is affixed to ring member 14 and is provided witha central hexagonal aperture 46 through which valve member 20 extends.Stem 30 of valve member 20 includes a hexagonal flange portion 48 and acylindrical portion 50 having a threaded exterior surface. Hexagonalaperture 46 and hexagonal flange 48 together form cooperating surfaceswhich allow movement of valve member 20 along axis A while preventingrotation of valve member 20 about axis A. As will be appreciated bythose skilled in the art, such axial movement of valve member withoutrotation may be achieved by differently shaped cooperating surfacesbetween retainer 44 and valve member 18.

Bonnet 24 partially surrounds annular retainer 44 and is welded to ringmember 14. In particular, bonnet 24 includes a cylindrical flange 24aaligned with and welded to a cylindrical flange 14b of ring member 14.The weld between bonnet 24 and ring member 14 may be such as to fullypenetrate to weld and fix annular retainer 44 to bonnet 24 and ringmember 14. As seen in the figures, flanges 14b and 24a include mutuallyfacing and connected flat surfaces, however such flanges may includemating stepped surfaces which aid in alignment of bonnet 24 and ringmember 14. Similarly, flanges 14a and 12a may also include matingstepped surfaces for easy alignment of ring member 14 and main valvebody 12.

Valve drive mechanism 22 includes a driver 52 provided with a threadedbore 54 which engages the threaded exterior surface of cylindricalportion 50 of stem 30. Both driver 52 and cylindrical portion 50 extendthrough a central aperture 56 of bonnet 24.

Driver 52 includes a flange portion 58 which is disposed between bonnet24 and retainer 44 such that driver 52 is free to rotate about axis Abut is prevented from moving along axis A. Handle 16 is coupled todriver 52 by means of a set screw with a conical tip which may bescrewed in bore 16a of handle to engage a complementarily shaped conicalseat 52a drilled in driver 52 such that a rotation of handle 16 urges alike rotation of driver 52.

Handle 16 includes a central aperture 62 in which a cap 64, attached torod member 32 and covering the head of rod member 32, is arranged. Thedegree of protrusion of cap 64 relative to the surface of handle 16provides an indication of the position (open or close) of valve member20.

Poppet 26 is arranged for axial movement inside chamber cavity 12d,while stem 30 extends outside of chamber cavity 12d. Rotation of handle16 moves valve member 20 along axis A between a closed position, inwhich a seal arrangement 70 arranged proximate first port 12f is engagedby poppet 26 so as to hermetically seal first port 12f, and an openposition in which poppet 26 is not engaged with seal arrangement 70 soas to permit fluid flow through first port 12f. Seal arrangement 70 willbe described in more detail hereinafter with particular reference toFIGS. 9-12.

An important feature of the invention described thus far is the weldmentbetween various parts of diaphragm valve 10. In particular, the weldmentcomprising main valve body 12, ring member 14, diaphragm 18, and valvemember 20 provide a reliable hermetic seal for chamber cavity 12d in anextremely cost-effective manner while using a limited number of partsand employing relatively inexpensive welding techniques. Welding ofbonnet 24 to ring member 14 provides further over-all cost efficiencyfor diaphragm valve 10, however the reliable hermetic sealing of chambercavity 12d is already provided by the weld connections between ringmember 14 and main valve body 12, and by the weld connections betweenthe inner and outer peripheries of diaphragm 18 and respectively valvemember 20 and ring member 14.

According to a preferred method of assembly of the various parts ofdiaphragm valve 10, inner periphery 40 of diaphragm 16 is welded topoppet 26 and outer periphery 42 of diaphragm 18 is welded to ringmember 14 to form a diaphragm/poppet/ring member assembly 72 (FIG. 4).These weldments are easily performed since them is little structure toblock access for welding tools.

Assembly 72 is then arranged so that ring member 14 is aligned with mainvalve body 12 with poppet 26 arranged in chamber cavity 12d, and ringmember 14 is then welded to main valve body 12. These simple operationsprovide a reliable hermetic seal for chamber cavity 12d substantially atmouth 12e. It is seen that the weld connections of diaphragm 18respectively to ring member 14 and valve member 20 are arrangedessentially inside or facing chamber cavity 12d. In conventionaldiaphragm valves, it is nearly impossible to weld the diaphragm to thevalve body "inside" the valve chamber cavity so as to provide a hermeticseal for the valve chamber cavity since access for welding is extremelylimited.

After washer 28 and stem 30 are connected to poppet 26, and retainer 44is arranged over diaphragm 18, and driver 52 is arranged over retainer44, bonnet 24 is aligned with ring member 14 and welded thereto, andhandle 24 is attached to driver 52. The assembly arrangement of threadedrod member 32, bore 34 in stem 30, aperture 36 in washer 28, andthreaded bore 38 of poppet 26 permits poppet 26 to be connected towasher 28 and stem 30 such that diaphragm 18 is not subjected topossibly damaging rotational shear stresses, since a tightening ofthreaded rod member 32 provides only an axial relative movement betweenthe facing surfaces of washer 28 and poppet 26 and diaphragm 18.

Main valve body 12, ring member 14, handle 16, bonnet 24, poppet 26,stem 30, rod member 32, retainer 44, and driver 52 are all preferablymade of 300 series stainless steel. Washer 28 is preferably made ofTeflon. Main valve body 12, ring member 14, and bonnet 24 are preferablyconnected by performing an inert gas TIG weld operation with back purgepumping of a pure (preferably in excess of 99.9999% purity) argonenvironment.

The preferred structure and welding of diaphragm 18 will now bedescribed with particular reference to FIGS. 4-6. Annular diaphragm 18is a unitary structure provided with a plurality of concentric ridges 80and valleys 82 which form a corrugation. Diaphragm 18 further includesan inner rim 84 at inner periphery 40 and an inner flange 86 extendingfrom inner rim 84, and an outer rim 88 at outer periphery 42 and anouter flange 90 extending from outer rim 88.

Diaphragm 18 is preferably made of a metallic material chosen from thegroup consisting essentially of nickel based stainless steels and 300series stainless steels. Most preferably, diaphragm 18 is made of anickel based stainless steel with a nickel content of at least 40percent by weight. An appropriate material for diaphragm 18 is a heattreatable Nickel-Iron Alloy known as Precision C (Ni-Span) availablefrom Hamilton Precision Metals, Inc. of Lancaster Pa. In a preferredmethod of manufacturing diaphragm 18, Precision C material in a fulldead soft annealed condition, without having been cold-rolled, is formedinto the shape of diaphragm 18 including inner flange 86 and outerflange 90. Precision C material in such state permits an easy formationof inner flange 86 and outer flange 90. After forming, diaphragm 18 isheat treated at approximately 1250° F. for about 3.5 hours, and then isair cooled such that the yield strength of diaphragm 18 is in excess of110,000 psi.

Inner flange 86 is accommodated in a cylindrical groove 92 of poppet 26,while the respective thicknesses of inner flange 86 and groove 92 areessentially the same (FIG. 5). A weld 94 connects the free edge of innerflange 86 to a stepped portion defined by groove 92. Weld 94 extendscircumferentially about axis D so as to provide a completely hermeticseal connection between diaphragm 18 and valve member 20 at innerperiphery 40. Inner flange 86 extends substantially parallel to axis D,and inner rim in cross-section extends substantially in a circular archaving a radius of curvature R_(i).

Diaphragm 18 further includes a substantially planar portion 96proximate inner rim 84. The dimensions of groove 92 and diaphragm 18 atinner periphery 40 are such that planar portion 96 rests against theannular surface 98 of washer 28 facing diaphragm 18 when washer 28 isconnected flush with poppet 26 without inner periphery 40 of diaphragm18 being substantially subjected to any stress.

Annular surface 98 of washer 28 is substantially planar but is providedwith an annular groove 100 adapted such that a first most inner ridge 80of the corrugation of diaphragm 18 is accommodated in annular groove 100without first ridge 80 making contact with surface 98 in all positionsof valve member 20. Annular groove 100 in cross-section preferablyextends over a circular arc of radius R_(w). Annular surface 98 ofwasher 28 includes a peripheral surface portion 102 adapted to engage afirst valley 82 of the corrugation of diaphragm 18. Annular surface 98provides an excellent stress protection of the welded connection ofinner periphery 40 of diaphragm 18 to poppet 26 since the flexure ofdiaphragm 18 as valve member 20 moves along axis A is moved away fromaxis A and away from the location of weld 94. While surface 98 isprovided on washer 28, a similarly shaped surface could be provideddirectly on stem 30 facing poppet 26, which would eliminate the need forwasher 28. The use of washer 28 is preferred however due to its materialproperties.

With reference to FIGS. 4 and 6, ring member 14 further includes aninternally projecting flange portion 14c, a cylindrical surface 14dextending about axis A, and a circumferential corner edge 14e. A weld104 connects the free edge of outer flange 90 to corner edge 14e of ringmember 14. Weld 104 extends circumferentially about axis D so as toprovide a completely hermetic seal connection between diaphragm 18 andring member 14 at outer periphery 42. When assembly 72 is connected indiaphragm valve 10 (FIG. 3), flange portion 14c is arranged over a faceof diaphragm 14 which is opposite chamber cavity 12d. In the non-flexedcondition of diaphragm 18, outer flange 90 preferably extends at anangle in the range of about 4.5 degrees to 5.5 degrees with respect toaxis D, and outer rim 88 in cross-section extends substantially in acircular arc having a radius of curvature R_(o). Most preferably, outerflange 90 extends at an angle of about 5 degrees with respect to axis D.The slightly flared structure of outer flange 90 provides improvedforming during the manufacture of diaphragm 18 as described previously.

The dimensions of cylindrical surface 14d, flange portion 14c, anddiaphragm 18 at outer periphery 42 are such that outer rim 88 contactsand rests against flange portion 14c when diaphragm 18 is in thenon-flexed condition without outer periphery 40 of diaphragm 18 beingsubstantially subjected to any stress.

Welds 94 and 104 are preferably formed in an electron beam (EB) weldingtechnique under vacuum and at low energy so as to form the completelyhermetic seal connections for diaphragm 18. The thickness of welds 94and 104 are substantially equal to the thickness of diaphragm 18.Location of welds 94 and 104 respectively at the stepped portion ofgroove 92 and corner edge 14e of cylindrical surface 14d facilitatesalignment and welding of diaphragm 18 in the welding operation.

The corrugation of diaphragm 18 facilitates flexure of diaphragm asvalve member 20 is moved along axis A. Diaphragm 18 may therefore havean increased thickness to increase the pressure capability of diaphragm18, while still being sufficiently flexible.

In order to further increase the pressure capability of diaphragmvalves, the present invention provides a diaphragm having stacked disks.FIG. 6a shows one embodiment of a stacked disk diaphragm according tothe present invention. Stacked disk diaphragm 18a includes diaphragm 18,welded to ring member 14 and poppet 26, as described previously, and atleast one stacked annular disk 18b stacked over diaphragm 18 andprovided with a plurality of concentric ridges and valleys to provide acorrugation that matches the corrugation of diaphragm 18. In a preferredmethod of assembly, two annular disks 18b are positioned over diaphragm18 without connecting annular disks 18b to diaphragm 18. Diaphragm 18 isthen welded to ring member 14 and poppet 26 to form a stackeddiaphragm/poppet/ring member assembly 72a, such that outer peripheralportions of annular disks 18b are interposed between flange portion 14cof ring member 14 and outer periphery of diaphragm 18. When washer 28and stem 30 are connected to poppet 26, inner peripheral portions ofannular disks 18b are interposed between surface 98 and inner peripheryof diaphragm 18. Annular disks 18b allow to further increase thepressure capability of diaphragm 18 while maintaining sufficientflexibility of stacked disk diaphragm 18a.

The provision of inner rim 84 and outer rim 88 advantageously reducesstress on weld 94 and weld 104 when diaphragm 18 flexes as valve member20 moves to different positions along axis A, since a large portion ofthe induced bending stresses to diaphragm 18 are concentrated at innerrim 84 and outer rim 88. Larger radiuses R_(i) and R_(o) are preferredfor better distribution of stress at inner rim 84 and outer rim 88. Amaximized radius R_(i) at inner periphery 40 is particularly importantsince diaphragm 18 sees more deflection at portions thereof closer toaxis A. Preferably, radiuses R_(i) and R_(o) are in the range of 0.010inch to 0.020 inch. Most preferably, radiuses R_(i) and R_(o) are about0.015 inch.

In one preferred embodiment in which diaphragm 18 is made of Precision Cmaterial as described above, the thickness of diaphragm 18 is in therange of 0.045 inch to 0.055 inch, radiuses R_(i) and R_(o) are in therange of 0.010 inch to 0.020 inch, outer flange 90 extends at an anglein the range of about 4.5 degrees to 5.5 degrees with respect to axis D,and inner flange 86 extends substantially parallel to axis D. Mostpreferably, the thickness of diaphragm 18 is about 0.050 inch, radiusesR_(i) and R_(o) are about 0.015 inch, outer flange 90 extends at anangle of about 5 degrees with respect to axis D, and inner flange 86extends substantially parallel to axis D. For these preferred and mostpreferred embodiments of diaphragm 18, the number of concentric ridges80 is preferably in the range of 2 to 4 while the number of concentricvalleys 82 is in the range of 2 to 4, while the height between ridges 80and valleys 82 is in the range of 0.015 inch to 0.025 inch. Mostpreferably, the number of concentric ridges 80 and the number ofconcentric valleys 82 are both four, and the height between ridges 80and valleys 82 is about 0.020 inch.

The preferred and most preferred embodiments of diaphragm 18 justdescribed are preferably formed in assembly 72 in which the diameter ofcylindrical surface 14d of ring member 14 is in the range of 1.434 inchto 1.436 inch, the height of cylindrical surface 14d is in the range of0.077 inch to 0.079 inch, the diameter of cylindrical groove 92 ofpoppet 26 is in the range of 0.221 inch to 0.223 inch, the height ofcylindrical groove 92 is in the range of 0.032 inch to 0.038 inch, andthe cross-sectional thickness of cylindrical groove 92 is in the rangeof 0.007 inch to 0.011 inch, while most preferably the diameter ofcylindrical surface 14d of ring member 14 is about 1.435 inch, theheight of cylindrical surface 14d is about 0.078 inch, the diameter ofcylindrical groove 92 of poppet 26 is about 0.220 inch, the height ofcylindrical groove 92 is about 0.035 inch, and the cross-sectionalthickness of cylindrical groove 92 is about 0.009 inch. For thesepreferred and most preferred embodiments of assembly 72, preferably thedepth of groove 100 of washer 28 is in the range of 0.020 inch to 0.030inch, the diameter of the center of groove 100 is in the range of 0.485inch to 0.495 inch, the radius R_(w) of groove is in the range of 0.057inch to 0.067 inch, and the outer diameter of surface 98 of washer is inthe range of 0.615 inch to 0.625 inch, while most preferably the depthof groove 100 of washer 28 is about 0.025 inch, the diameter of thecenter of groove 100 is about 0.490 inch, the radius R_(w) of groove isabout 0.062 inch, and the outer diameter of surface 98 of washer isabout 0.620 inch.

While the foregoing describes an annular diaphragm through which anelongated valve member extends, the invention is also operable indiaphragm valves which include circular diaphragms which are flexiblymovable in a central axis direction between closed and open positions.As will be appreciated by those skilled in the art, in its closedposition the circular diaphragm may engage substantially directly withan inlet port of the diaphragm valve for hermetic sealing thereof, oralternatively a sealing poppet may be arranged in the chamber cavitywhich is engaged by the central portion of the circular diaphragm in itsclosed position such that the sealing poppet substantially makeshermetic sealing contact with the inlet port of the diaphragm valve. Inboth cases, a stem arranged outside of the valve chamber cavity may beprovided for engagement with the central portion of the circulardiaphragm such that the central portion flexibly moves in a central axisdirection between closed and open positions. The diaphragm valveincluding such a circular diaphragm could have a ring member welded to amain valve body, and an outer periphery of the circular diaphragm weldedto the ring member, in a manner as described previously. In such a case,the weldment including the main valve body, the ring member, and thecircular diaphragm would provide a reliable hermetic seal for thechamber cavity of the diaphragm valve.

FIGS. 7 and 8 illustrate valve diaphragm 10 with valve member 20respectively in its fully closed sealing position and in its fully opennon-sealing position. Planar surface 12i of chamber cavity 12d of mainvalve body 12 acts to stop further movement of valve member 20 past itsfully closed position (FIG. 7), while flange 58 of driver 52 acts tostop further movement of valve member 20 past its fully open position byengagement with flange 48 of stem 30 (FIG. 8).

In both the open and closed positions, the shape of diaphragm 18 nearinner periphery 40 remains essentially unchanged due to surface 98 ofwasher 28. In particular, planar portion 96 remains substantiallyplanar, the first most inner ridge 80 remains accommodated in groove 100without engaging the surface of groove 100, and the two most innervalleys 82 remain engaged substantially at the edges of groove 100 atsurface 98.

In the open position, ridges 80 of the corrugation of diaphragm 18engage with a surface 44a of retainer 44 which faces diaphragm 18.Surface 44a of retainer 44 thereby provides support to diaphragm 18 whenvalve member 20 is in its open position, so as to increase the pressurecapability of diaphragm valve 10 by increasing the pressure/loadresistance of diaphragm 18. Surface 44a is sloped and preferably extendsat an angle between about 4.5 degrees and 5.5 degrees with respect to aplane which is perpendicular to axis A. Most preferably, sloped surface44a has an angle of about 5 degrees (in the range of 4.9 to 5.1degrees). In the most preferred embodiments described herein, diaphragmvalve 10 has been found to be capable of adequately handling pressuresof at least 375 psi. While retainer 44 admirably provides sloped surface44a for supporting diaphragm 18, it is envisaged that flange portion 14cof ring member 14 could internally protrude farther so as to itselfprovide a sloped surface such as to function in a manner similar tosloped surface 44a. Flange portion 14c of ring member 14 could extendeven far enough to provide a central aperture with an internal surfacesuch as to function in a manner similar to central aperture 46 ofretainer 44. Alternatively, retainer 44 could be formed to include aportion which replaces the functionality of flange portion 14c.

Seal arrangement 70 will now be described with particular reference toFIGS. 9-12. Seal arrangement 70 includes a circumferential groove 110provided in planar surface 12i of main valve body 12 and extending so asto surround inlet port 12f, and an elastic sealing material 112 which isat least partially disposed in circumferential groove 110. Sealingmaterial 112 includes an extension portion 114 partially extending fromcircumferential groove 110 past surface 12i in a non-engaged andnon-compressed state i.e. when valve member 20 is not in its closedposition.

Circumferential groove 110 is configured so as to provide at least onevoid 116,117 between extension portion 114 and sidewall portions110a,110b of groove 110 in a non-compressed state of portion 114 (FIG.11), such that material of extension portion 114 can at least partiallyfill void 116,117 when valve member 20 is in its closed position (FIG.12), and such that extension portion 114 can return to substantially itsoriginal configuration when valve member 20 returns to its openposition.

Sealing material 112 is preferably a single polymerchlorotrifluoroethylene with zero water absorption characteristics perASTM D570. Most preferably, sealing material is Kel-F 81 materialavailable from 3M Corporation of Minneapolis Minn.

Sealing material 112 is an annular sealing ring having a base portion118 and extension portion 114. Base portion 118 is substantiallyrectangularly shaped in cross-section i.e. with four sides having sharpor curved corners, and extension portion 114 is substantially wedgeshaped in cross-section i.e. with a pair of converging sides extendingpast surface 12i.

Groove 110 is also substantially rectangularly shaped in cross-sectioni.e. with four sides having sharp or curved corners. Base portion 118engages sidewall portions 110a of groove 110 (FIG. 11). Base portion 118has removed portions or rounded corners 118a,118b so as to provide voidspace 120,122 between corners 118a,118b and rounded corners 110c,110d ofgroove 110, in order to facilitate insertion of elastic sealing material112 in groove 110.

Extension portion 114 defines converging sloping surfaces 114b,114cextending beyond surface 12i and a circumferential apex 114a formed bysurfaces 114b,114c. Sloped surfaces 114b,114c preferably have anincluded angle relative to apex 114a of between about 29.5 degrees and30.5 degrees, and most preferably of about 30 degrees.

While the preferred form and shape of groove 110 and elastic sealingmaterial 112 have been described herein, it will be appreciated thatgrooves and sealing materials of other shapes and forms may be employedin a manner such that the sealing material disposed in the groove has adimension that is greater than the groove depth so that a portion of thesealing material extends out of the circumferential groove past thesurface in which the groove is circumferentially provided about a port,and such that a gap is provided in the groove proximate the surface. Thegroove should have a substantially constant groove depth, and thesealing material should be chosen such that at least a portion of theextending portion can be elastically compressed into the gap by theexertion of a force on such extending portion, substantially without anypermanent plastic deformation so that the sealing material will returnto its original form upon removal of the exertion of such force. In thismanner, a seal arrangement is provided which is extremely durable andreliable even after many cycles of application and removal of thesealing force.

Groove 110 has been swaged such that at least a portion of sidewall 110aprovides a clamping force on sealing material 112 to retain it withingroove 110 after it has been inserted within groove 110. FIG. 11 showsoriginal sidewall 110a' of groove 110 and swaged sidewall 110a. FIG. 10illustrates a preferred method of swaging for groove 110. Afterinsertion of sealing material 112 in groove 110, a conically shapedswage tool 124 is engaged in inlet port 12b and force F is exerted onswage tool 124 to create swaging forces F_(s) on groove 110 such that atleast a deformed portion of sidewall 110a is formed to grip and retainsealing material 112. FIG. 11 also illustrates an original sidewallportion 124' of inlet port 12b and a deformed sidewall portion 124 ofinlet port 12b which has been formed after the swaging operation.

FIG. 13 illustrates another embodiment of a diaphragm valve according tothe present invention, similar to diaphragm valve 10 describedpreviously except that ring member 14 has been eliminated. A bonnet tovalve body weld connection 10' includes a bonnet 24' welded directly toa main valve body 12'. Main valve body 12' may be completely similar tovalve body 12 described previously except that it includes a flange 12a'welded directly to bonnet 24', and an internally projecting clampportion 12k'. A diaphragm 18' includes an outer periphery 42' which isclamped between clamp portion 12k' and a retainer 44'. Diaphragm 18' inthis case is a substantially planar circular diaphragm.

In a preferred method of clamping outer periphery 42' between retainer44' and main valve body 12', outer periphery 42' is arranged betweenclamp portion 12k' and retainer 44', bonnet 24' is arranged overretainer 44' such that flange 24a' of bonnet 24' makes contact withflange portion 12a' and retainer 44' is positioned between bonnet 24'and clamp portion 12k' with outer periphery 42' of diaphragm 18'arranged between retainer 44' and clamp portion 12k'. Flange 24a' ofbonnet 24' is then preferably pressed against flange 12a' of valve body12', and then flange 24a' is simultaneously welded directly to flange12a', preferably by using a TIC welding technique, to form weld 126. Thewelding operation initially expands the material of flanges 12a' and24a', and upon cooling such material of flanges 12a' and 24a' contractsto produce induced stresses in such material which provides a clampingforce on outer periphery 42' of diaphragm 18' between retainer 44' andclamp portion 12k'. In the preferred method, the initial pressing offlange 24a' to flange 12a' provides an initial clamping force on outerperiphery 42', and the welding provides a final clamping force on outerperiphery 42' which is even greater than the initial clamping force.

The clamping force on outer periphery 42' of diaphragm 18' is such as toprovide a completely hermetic seal for chamber cavity 12d' at outerperiphery 42'. Since diaphragm 18' is circular in shape clamping ofouter periphery 42' alone provides the hermetic seal for chamber cavity12d'.

Diaphragm 18' could be substituted with an annular diaphragm in whichcase the inner periphery thereof could be welded to a valve member forexample in a manner as described previously so as to also provide acompletely hermetic seal for chamber cavity 12d' at the inner periphery.Bonnet 24' and retainer 44' are shaped so as to support a valve memberand a valve drive mechanism similar to those elements describedpreviously. Furthermore, bonnet 24' could be provided with a portionwhich engages directly on outer periphery 42' without the interpositionof retainer 44' such that outer periphery 42' is sealingly clampedbetween such bonnet portion and clamp portion 12k' after creating weld126. In the embodiment of FIG. 13, just as in various embodiments of thepreceding Figures, a diaphragm valve has been provided which includes aflexible diaphragm coupled to the valve body proximate its outerperiphery, and which also includes a bonnet covering the diaphragm andbeing non-releasably coupled to the valve body by at least one weld suchthat the diaphragm is non-releasably secured within the bonnet.

The invention as described herein is particularly useful for controllingfluid flow in apparatus for manufacturing semiconductors where highpurity gases are being transported and leakage must be avoided.

Although the invention has been described with particular reference todiaphragm valves, it will be appreciated that the invention has broaderapplications, and that certain individual features thereof may be usedwith other types of valves and/or in other environments. To give justone example, while seal arrangement 70 performs admirably in diaphragmvalves 10 as described herein, it is envisaged that seal arrangement 70is useful in any type of assembly where reliable sealing of a port isrequired.

While this invention has been described in terms of several preferredembodiments, it is contemplated that various alterations andpermutations thereof will become apparent to those skilled in the art.It is therefore intended that the appended claims include all suchalterations and permutations as fall within the true spirit and scope ofthe present invention.

I claim:
 1. A method of forming a seal between a cavity in a valve bodyof a diaphragm valve and a port provided in said valve body,comprising:providing a circumferential groove in a surface of said valvebody surrounding said port; disposing an elastic sealing material insaid groove, said sealing material having an extension portion which atleast partially extends out of said groove past said surface of saidvalve body, and said sealing material being configured to provide a voidwithin said groove between said extension portion and a sidewall of saidgroove; and bringing a valve member into a closed position in which saidvalve member closes said port and elastically compresses said extensionportion such that said extension portion at least partially fills saidvoid within said groove.
 2. A method of forming a seal according toclaim 1 wherein said sealing material is an annular sealing ring havinga base portion and said extension portion, said base portion having asubstantially rectangularly-shaped cross-section and said extensionportion having a substantially wedge-shaped cross-section.
 3. A methodof forming a seal according to claim 2 wherein said extension portionincludes a circumferential apex defined by converging sloped surfaces.4. A method of forming a seal according to claim 3 wherein said slopedsurfaces have an included angle relative to said apex of between about29.5 degrees and about 30.5 degrees.
 5. A method of forming a sealaccording to claim 1 wherein said sealing material is comprised of asingle polymer chlorotrifluoroethylene.
 6. A method of forming a sealaccording to claim 2 wherein said sealing material is comprised of asingle polymer chlorotrifluoroethylene.
 7. A method of providing a sealarrangement in a diaphragm valve which includes a port provided in avalve body, the method comprising the steps of:providing acircumferential groove having a substantially constant groove depth in asurface of said valve body surrounding said port; disposing a sealingmaterial in said circumferential groove having a dimension that isgreater than said groove depth, such that a portion of said sealingmaterial extends out of said circumferential groove past said surface ofsaid valve body, said sealing material being configured to provide a gapwithin said circumferential groove proximate said surface; and swagingsaid circumferential groove such that at least a portion of a sidewallof said circumferential groove provides a clamping force on said sealingmaterial to retain said sealing material within said circumferentialgroove; said gap within said circumferential groove being present afterswaging; whereby at least a portion of said portion of said sealingmaterial can be compressed into said gap by the exertion of a force onsaid portion of said sealing material that extends out of said groove.8. A method of providing a seal arrangement according to claim 7 whereinsaid swaging step includes engaging a cortically shaped swage tool withsaid port and exerting a force on said swage tool so as to exert aswaging force on said circumferential groove such that said at least aportion of a sidewall of said circumferential groove deforms to gripsaid sealing material.
 9. A method of providing a seal arrangementaccording to claim 7 wherein said at least a portion of said portion ofsaid sealing material can be compressed elastically into said gapsubstantially without any permanent plastic deformation and can returnto its original form upon removal of the exertion of said force.
 10. Amethod of providing a seal arrangement according to claim 7 wherein saidsealing material is an annular sealing ring having a base portion whichis substantially rectangularly-shaped in cross-section and an extensionportion which is substantially wedge-shaped in cross-section.
 11. Amethod of providing a seal arrangement according to claim 10 whereinsaid extension portion includes a circumferential apex defined byconverging sloped surfaces.
 12. A method of providing a seal arrangementaccording to claim 11 wherein said sloped surfaces have an includedangle relative to said apex of between about 29.5 degrees and about 30.5degrees.
 13. A method of providing a seal arrangement according to claim7 wherein said sealing material is comprised of a single polymerchlorotrifluoroethylene.
 14. A method of providing a seal arrangementaccording to claim 10 wherein said sealing material is comprised of asingle polymer chlorotrifluoroethylene.
 15. A method of forming a sealbetween a cavity in a valve body of a diaphragm valve and a portprovided in said valve body, said valve having an open position and aclosed position, comprising:providing a circumferential groove in asurface of said valve body surrounding said port; disposing an elasticsealing material in said groove, said sealing material having anextension portion which extends out of said groove past said surface ofsaid valve body when said valve is in an open position, and said sealingmaterial being configured to provide a void within said groove betweensaid extension portion and a sidewall of said groove; bringing a valvemember into a closed position of said valve in which said valve membercloses said port and elastically compresses said extension portion intosaid groove such that said extension portion partially fills said voidwithin said groove; and bringing said valve member into said openposition of said valve in which said valve member opens said port andreleases said extension portion from said groove such that saidextension portion returns to an original shape substantially without anyplastic deformation.
 16. A method of forming a seal according to claim15 wherein said sealing material is an annular sealing ring having abase portion and said extension portion, said base portion having asubstantially rectangularly-shaped cross-section and said extensionportion having a substantially wedge-shaped cross-section.
 17. A methodof forming a seal according to claim 16 wherein said extension portionincludes a circumferential apex defined by converging sloped surfaces.18. A method of forming a seal according to claim 17 wherein said slopedsurfaces have an included angle relative to said apex of between about29.5 degrees and about 30.5 degrees.
 19. A method of forming a sealaccording to claim 15 wherein said sealing material is comprised of asingle polymer chlorotrifluoroethylene.
 20. A method of forming a sealaccording to claim 16 wherein said sealing material is comprised of asingle polymer chlorotrifluoroethylene.